Refractory masses



United States Patent 3,345,192 REFRACTORY MASSES Albert Hloch and Rudolf Kohlhaas, Frankfurt am Main, and Nikolaj Medi and Helmut Neises, Kelkheim,

3,345,192 Patented Oct. 3, 1967 ice phosphoric `acid should be such that the ratio of the A1202 content of the reactive aluminum compound to the P205 content of the mixture of these components be within the range of 1:1.5 to 1:4.

Taunus, Germany, assignors to Farbwerke Hoechst Ak- 5 The green strength can be further increased, without the flellgesellschaft VOIIPIS Meister LUCIUS 8l B'l'lllllllg, mechanical properties of the refractory masses being imiarlrlnkg? am M2111 Germany, a Corporation 0f paired, by using a mixture of a gel of hydrate of alumina and aluminum fluoride as reactive aluminum compound. Filed Nov. 16 1965 Ser. No. 508,101 Claims priority, application Germany, Dec. 9, 1964, The total miniem of. alummpm uonde m the refratory 4,648 10 mass comprising a high melting filler, a reactive aluminum 2 (112mm (CL 106 67) compound and polyphosphoric acid, shall not exceed 3% The improving effect of the addition of aluminum uo- ABSTRACT 0F THE DISCLOSURE ride to the refractory masses in accordance with the in- A refractory mass comprised of an inert filler (such ,Xntlorff lugatilclilarly. Srlsmg snc tle know; 'addl as chamotte) ball clay, alumina hydrate and polyphossli gig addtoe ulpme. enecncathproper Iets. ani phoric acid is improved by adding to it aluminum fluorerractg al Doh; nona? o e cnventlxona ride. Thus modified, the refractory mass exhibits improved A er'ctiv 8851s .ruy Proves d e geen s feng d' green strength 4as well as a reduced setting time. These 2 ta eul beeuselm mwmklgl s 1ere fmhayd a tva properties are obtained as a result of the coaction of alu- 0 algm. ayThe au ed .n g sf; y .rlebau minum fluoride with the other components of the refracd; uvl'ch 713;? ige ert yalu bmra ne W; ct.v tory mass, eg., polyphosphoric acid. ys. n p s e aga e as ea 1 e aluminum compounds.

The following exampes serve to illustrate the invention The present invention relates to refractory masses havbut they are not Intended to hmlt 1t thereto' ing au improved green strength and a reduced setting time. Exam l p es As cemeuts, mortars and rammmg masses for reproof linings and masonry there are increasingly used masses The test mixtures were made from the following matecomprising a high melting filler, for example chamotte, a rials: chamotte powder (A1203 content 40 to 41%, grain reactive aluminum compound, for example, mullite, cosize max. 0.3 mm.), ball clay (Geisenheim) 17% of rundum, bauxite, hydrargillite or kaolin, and a solution of A1203, gel of hydrate of alumina (H2804) 49% of A1203, an acid aluminum phosphate, the acid aluminum phospolyphosphoric acid (84% of P205), A1F2.3H20, comphate producing setting of the masses by reacting with the mercial quality. reactive aluminum compound. Such masses are distin- Refractory mortar mixtures, one of each two containguished by a high refractoriness and can be exposed in ing ortho-phosphoric acid and the other containing polycontinuous service to temperatures of up to about 1600 phosphoric acid, as binder, were compared with regard C., depending on the refractoriness of the filler. They sufto their green Strength and setting time. Care was taken fer, however from a poor green strength and long setting that the relative amount of P205 and A1203 and also the time which render it difficult to work without interruption, ratio A12031P205 were the same in each two mixtures. for example, when lining furnaces. By adding water-solu- The following table indicates the composition of reble fluorides, especially ammonium fluoride, the setting fractory mortar with orthophosphoric acid (58% of time can be reduced whereby, however, the mechanical P205) according to Tests Nos. 2, 4, 6 and 8 and that of properties are impaired. refractory mortar with polyphosphoric acid (84% of Now We have found that refractory masses comprising P205) according to Tests Nos. 1, 3, 5 and 7. The strength a high melting filler, a reactive aluminum compound and values of test samples 1-4 are shown by the accompanyan acid binder which have a reduced setting time and an ing graph. It is evident from the graph that the mortar improved green strength can be Iobtained by using, as masses obtained with polyphosphoric acid are superior binder, 3 to 15% by weight, advantageously 6 to 8% by with regard to their green strength which increases so weight, of polyphosphoric acid containing at least of 50 strongly, particularly in the presence of AlF3, that rupture P205 the percentage figures being calculated on the total in many cases occurs in the test brick and not in the mass. The ratio of reactive alumnium compound to polymortar layer.

TABLE Extremely low Extremely high P205 content P205 content Composition Test 1, Test 2, Test 3, Test 4, percent percent percent percent Test 5, Test 6, Test 7, Test 8, percent percent percent percent Phosphon'c acid, 58% P205-.- 8. 5 11.5 4. 5 22. 0 Polyphosphoric acid, 84% P20 0 8. O 3. 0 15.0 Gel of hydrate oi' alumina 49% A1203 2. 5 2. 5 3. 5 3. 5 1. 5 l. 5 7.0 7.0 Aiuminum fluoride Autismo 2. 0 2.0 0.5 o. 5 3. 0 3. o

Geisenheim clay 20 20 15 15 15 15 15 15 Chamotte 71. 5 59. o 71. 5 es so 7s. 5 6o 53 Green tensile strength in k cm After i week 7 3 28 4 10 4 1. 2 0. 5 After 2 weeks..- i9 s 30 9 11 4. 5 1. 5 0. 5 After 3 weeks 21 13 3o 14 13 7 3. 5 1

Test samples Nos. 1 and 2, Nos. 3 and 4, Nos.

5 and 6, and Nos. 7 and 8, respectively, have the same contents of P205.

We claim:

1. rA refractory mass consisting `essentially of 60 to 80% by Weight of an inert refractory filler, 15 to 20% by weight of ball clay, 1.5 to 7% by weight of alumina hydrate, 3 to 15% by weight of polyphosphoric acid containing at least 80% of P205 and 0.5 to 3.0% by weight of aluminum uoride.

V2.1A refractory mass according to claim 1 wherein the polyphosphoric acid is from 6 to 8% by weight.

4 References Cited UNTED STATES PATENTS 3/ 1953 Robinson 106-65 9/ 1958 Hansen et al 106--65 TOBIAS E. LEVOW, Primary Examiner.

J. POER, Assistant Examiner. 

1. A REFRACTORY MASS CONSISTING ESSENTIALLY OF 60 TO 80% BY WEIGHT OF AN INERT REFRACTORY FILLER, 15 TO 20% BY WEIGHT OF BALL CLAY, 1.5 TO 7% BY WEIGHT OF ALUMINA HYDRATE, 3 TO 15% BY WEIGHT OF POLYPHOSPHORIC ACID CONTAINING AT LEAST 80% OF P2O5, AND 0.5 TO 3.0% BY WEIGHT OF ALUMINUM FLUORIDE. 